Despite the introduction of insulin into clinical practice in 1922, diabetes mellitus remains a devastating disease. Like current therapies for many other ailments, insulin essentially transformed diabetes from acute and lethal to chronic and debilitating. The dissertation addresses this troubling phenomenon by studying the history of diabetes--what was known about it, what was done for it, how it affected patients and physicians--from 1922 to 1970, when the chronicity .of diabetes began to be seen as a major problem. The study broadly aims to better our knowledge of diabetes as a chronic disease and to explore the more general issue of how to deal with chronic outcomes of 'successful' medical interventions. This project will use standard methods of social and intellectual history scholarship, including a qualitative and statistical analysis of diabetic patient letters and records (200 records divided into five cohorts, randomly selected, of patients first seen in 1922, 1926, 1932, 1942, 1952). Specifically, it will 1) examine how medical treatment has affected the natural history of diabetes, and how the medical community and society has responded to the new population of chronic diabetics; 2) analyze the negotiation between doctors, patients, and families regarding how the illness was to be managed and who was responsible for the management and its outcome; and 3) provide a historical framework to help the medical and lay communities rethink their fundamental assumptions about medical care and their priorities for the medical system of the future.